Use of isothiocyanobenzoxazoles and isothiocyanobenzimidazoles as anthelmintics

ABSTRACT

ISOTHIOCYANO-SUBSTITUTED 2-PHENYL- AND 2- PHENYLALKYLBENZOXAZOLES AND -BENZIMIDAZOLES ARE DISCLOSED AS NOVEL ANTHELMINTIC AGENTS. THEIR PRODUCTION, THEIR USE IN THE CONROL OF HELMINTHS AND COMPOSITIONS CONTAINING THEN ARE ALSO DESCRIBED. 2-(4&#39;&#39;-ISOTHIOCYANOPHENYL)-BENZIMIDAZOLE AND -BENZOXAZOLE ARE REPRESENTATIVE COMPOUNDS OF THIS NOVEL CLASS OF ANTHELMINTICS.

United States Patent 3,822,356 USE OF ISOTHIOCYANOBENZOXAZOLES AND ISOTHIOCYANOBENZIMIDAZOLES AS ANT- HELMINTICS Paul Brenneisen and Alfred Margot, Basel, Switzerland, assignors to Ciba-Geigy Corporation, Ardsley, N.Y. No Drawing. Original application July 24, 1968, Ser. No. 747,122, now Patent No. 3,586,670. Divided and this application Feb. 1, 1971, Ser. No. 111,655

Int. Cl. A611; 27/00 US. Cl. 424-272 9 Claims ABSTRACT OF THE DISCLOSURE Isothiocyano-substituted Z-phenyland 2 phenylalkylbenzoxazoles and -benzimidazoles are disclosed as novel anthelmintic agents. Their production, their use in the control of helminths and compositions containing them are also described. 2-(4'-isothiocyanophenyl)-benzimidazole and -benzoxazole are representative compounds of this novel class of anthelmintics.

This application is a Divisional of US. Application Ser. No. 747,122, filed July 24, 1968, and now US. Pat. 3,586,- 670, issued June 22, 1971.

The present invention concerns new isothiocyanobenzazole derivatives and more particularly benzoxazole and benzimidazole derivatives, processes for the production thereof as well as the use of the new compounds for controlling parasitic helminths and anthelmintic agents containing such active substances.

Of the endoparasites occurring in warm blooded animals, helminths cause grave injuries. For example, not only is the growth or increase in weight of infested animals retarded but often injuries occur as a result of which the animals can die. It is thus of great importance to develop agents for use in veterinary and human medicine which are suitable for the combatting of helminths in all their stages of development and which are also suitable for prevention of infestation of warm-blooded animals by these pests. Although a series of substances having an anthelmintic action is known, such substances are often not completely satisfactory; either they have an insufficient action in tolerable dosages, there are undesirable side effects in therapeutically effective dosages, or they have an unduly narrow spectrum of activities.

The term helminth as used in the present specification and claims refers to nematodes, cestodes and trematodes, i.e. especially worms infesting the gastro-intestinal tract, the liver and other organs of warm-blooded animals.

The present invention provides novel isothiocyanobenzazoles of the general formula I wherein one or two of the substituents R through R, represent the isothiocyano group and the remaining ones of these substituents represent hydrogen, chlorine, bromine, the hydroxyl, nitro, trifluoromethyl, carboxyl or carbamoyl group, or a lower alkyl, lower alkoxy, lower alkylthio, lower alkylamino, lower alkoxy-carbonyl, di-(lower alkyl)-substituted carbamoyl, di-(lower alky1)-substituted amino, lower alkanoyl amino, lower alkenyloxy, lower alkenylthio, lower alkanoyloxy or lower alkanoyl group, while Patented July 2, 1974 R and R together with the carbon atoms to which they are linked may also represent a benzene ring fused to ring A;

X represents oxygen or the grouping N-R wherein R represents hydrogen, a lower alkyl radical any substituent of which is selected from di-(lower alkyl)- amino, benzoyl and halogeno-benzoyl or the benzyl or a phenyl radical which may be substituted by lower alkyl, or a lower alkanoyl or an unsubstituted or halogeno-substituted benzoyl radical;

Z represents an aliphatic bridging member having two carbon atoms, and

n represents 0 or 1;

and wherein any isothiocyano group must occupy a position other than ortho to any hydroxyl or alkylamino group present at the same ring, and, in those compounds in which X represents NH and n is equal to 0, R and R do not represent isothiocyano groups, as well as those salts of the compounds of formula I which are well tolerated by Warm-blooded animals in anthelmintically effective doses, are of excellent anthelmintic activity and are useful in controlling parasitic helminths in warmblooded animals.

In those compounds of formula I which contain the aliphatic bridge member Z the latter is preferably one of the groupings CH CH and CH=CH.

In particularly preferred compounds of Formula I, X represents NR wherein the substituent R represents preferably hydrogen, in next preferred ones the methyl, benzyl, N-N-dimethylaminoethyl, phenacyl, a bromo-phenacyl or a tolyl group, and in a third preferred group, the acetyl or benzoyl or a chlorobenzoyl group.

The term lower used in defining alkyl groups including those occurring in alkylamino, alkoxy and alkylthio radicals means that such radicals have from 1 to 4 carbon atoms, lower alkenyl radicals have preferably 3 to 4 carbon atoms, and lower alkanoyl groups including those occurring in alkanoyloxy and alkanoylamino radicals have preferably from 2 to 5 carbon atoms. Most preferred compounds, however, have a methyl group as alkyl and an acetyl group as alkanoyl substituents or substituent moieties.

Among the anthelmintically active salts of compounds falling under the general formula I which are addition salts of the latter compounds with suitable inorganic or organic acids the hydrochlorides are particularly preferred.

The new benzazoles of the general formula I substituted in 2-position by a monoor di-nuclear aromatic or araliphatic radical and by one or two isothiocyano groups are produced according to the invention by reacting a benzazole substituted by a monoor di-nuclear aromatic or araliphatic radical and by at most two primary amino groups in the ring, with a reagent capable of introducing the thiocarbonyl group into amino groups. The reaction is preferably performed in the presence of a solvent or diluent which is inert to the reaction partners.

The following reagents are preferably used in the process according to the invention to introduce a thiocarbonyl group:

(b) a bis-thiocarbamoyl sulphide of the general formula III g alkyl (III) wherein the index In represents 1 or 2, and alkyl is preferably ethyl, in the presence of hydrogen halide;

(c) bis-trichloromethyl pentathio-dipercarbonate;

(d) ammonium rhodanide in the presence of gaseous hydrogen chloride;

(e) phosgene and phosphorus pentasulfide;

(f) carbon disulfide in the presence of an inorganic or organic base, whereby the amino group is first converted into the corresponding dithiocarbamic salt which is subsequently dehydrosulphurised to the isothiocyano p;

(g) ammonium rhodanide and benzoyl chloride, and thermal decomposition to the isothiocyano derivate of the intermediary thiourea;

(h) carbon disulfide and dicyclohexylcarbodiimide in the presence of a tertiary amine.

The reaction with thiophosgene is performed, e.g. according to Houben-Weyl, 4th Edition, Vol. 9, pages 867 and ff. (1955), using acid binding agents according to O. E. Schultz in Arch. Pharm. 295, 146-151 (1962); the reaction with N,N-diethylthiocarbamoyl chloride is performed according to J. Org. Chem. 30, 2465 (1965); that with bis-thiocarbamoyl sulphides according to F. H. Marquardt, Helv. Chim. Acta, 49, 1716; that with bis-trichloromethyl pentathio-dipercarbonate is performed according to R. Gottfried, Angew. Chem. 78, 985 (1966); that with ammonium rhodanide and gaseous HCl is performed according to British Pat. No. 1,099,768, and that with phosgene and phosphorus pentasulfide according to Houben-Weyl, 4th Edition, Vol. 9, pages 867 and ff. (1955).

The dehydrosulphurisation following the reaction with carbon disulfide and base can be performed oxidatively with metal salts (British Pat. No. 793,802, Dutch Pat. No. 81,326) e.g. with lead, copper, zinc or iron III-salts, iodine, alkali metal hypochlorites or chlorites, preferably with sodium and potassium salts (French Pat. No. 1,311,855), also with suitable acid halides such as phosgene and phosphorus oxychloride [D. Martin et al., Chem. Ber. 98, 2425-2426 1965)], also with C1 and ammonium sulphide (DAS 1,192,189) or with chloramine T (British Pat. No. 1,024,913).

The reaction with ammonium rhodanide and benzoyl chloride leading first to the thiourea derivative which is then thermally decomposed, e.g., in boiling chlorobenzene to the isothiocyano derivative is performed, e.g., according to Houben-Weyl, 4th Edition, Vol. 9, pages 867 and if. (1955 and the reaction with carbon disulfide and dicyclohexyl-carbodiimide in the presence of a tertiary amine is performed according to J. C. Jochims, Chem. Ber. 1746 (1968).

The benzazole derivatives of general formula I can further be obtained by cyclisation reaction of an N-(2-hydroxyphenylor 2-sec.amino-phenyl)aldimine of a benzaldehyde, cinnamaldehyde or 2-phenylpropionaldehyde, the aldimine being substituted by 1 or 2 isothiocyano groups. This reaction is performed with a mild oxidising agent such as nickel peroxide or lead tetra-acetate [Chem. Soc. 1949, 2971, Chem. Abstr. 62, 541 h (1965)], also with chloranil in xylene [Chem. Soc. 1950, 1722] and nitrobenzene [Chem. Abstr. 62, 1639( 1965)].

The new benzazoles of general formula I which contain a group capable of salt formation can be converted into the corresponding salts with acids which are nontoxic to the human and animal organism and are of suffi- S alkyl -N alkyl alkyl cient strength to react with said group. Inorganic and organic acids can be used, e.g. hydrohalic acids, sulphuric acid, phosphoric acid, oxalic acid, methane-sulphonic acid, p-toluene-sulphonic acid, etc.

The aminobenzazoles serving as starting materials can be prepared, e.g., according to the following known processes:

(1) Reaction of ortho-phenylenediamines or orthoamino-phenols resp. with aminobenzoic acids, aminocinnamic acids or aminophenyl-propionic acids resp. or the acid derivatives thereof in polyphosphoric acid as the condensing agent [J. Am. Chem. Soc. 79, 427 (1957)].

(2) Reaction of ortho-phenylendiamines or orthoamino-phenols with aminoor nitrobenzoic acids, cinnamic acids or phenylpropionic acids resp. in metaphosphoric acid ester as the condensing agent (Chem. and Pharm. Bull. (Japan) 12, 773 1964)]. Nitro-benzazoles thus obtained are then reduced to the corresponding amino-benzazoles by known methods.

(3) Reaction of ortho-phenylenediamines or orthoamino-phenols resp. with an aldehyde corresponding to the acids as used under (1) and (2) above, in the presence of a mild oxidising agent, e.g., with the sodium bisulfite adduct of the corresponding aldehyde [1. Het. Chem. 2, 453 (1963) The aminobenzazoles serving as starting materials can be used both in the form of the free bases as well as addition salts with acids, particularly mineral acids. The usual solvents are used for the processes according to the invention such as organic solvents which are inert to the reaction components, e.g. aromatic hydrocarbons, aliphatic and aromatic halogenated hydrocarbons, ether and ether-type compounds, water or mixtures of such solvents with water.

The benzazole compounds according to the invention and their salts have marked anthelmintic activity against the most important nematodes (i.e. Ascaridae, Trichostrongyloidae, Ancyclostromatidae, Strongyloidae), cestodes (Le. Anoplocephalidae, Taeniidae) and trematodes (i.e. Fascioloidae, Schistosomidae) which infest warmblooded animals including humans. Control of helminths is particularly important in the case of domestic and farm animals, e.g. cattle, hogs, horses, sheep, goats, cats, dogs and poultry. The compounds according to the invention can be administered to the aforesaid animals as a single dosage or repeatedly. In some cases, a better action is attained by protracted administration or smaller total dosages can be used. The active substances or mixtures containing them can also be added to the feed or drink, in which case the concentrations of active substance lie be tween 0.01 and 1%.

The new benzazole compounds and their salts which are non-toxic to the organism, can be administered in the form of solutions, emulsions, suspensions (drenches), powders, tablets, drages, boluses and capsules, either orally or by stomach tube.

The usual solid carriers such as kaolin, talcum, bentonite, sodium chloride, calcium phosphate, hydrocarbons, cellulose powders, cotton seed meal, carbowaxes, gelatine; or liquids such as water, if desired with the addition of surface active substances such as ionic or non-ionic dispersing agents, oils and other solvents which are not injurious to the animal organism, serve for the preparation of the forms for administration listed above. If the anthelmintic agents are in the form of feed concentrates, then carriers are, e.g. formulated foods, cereal feeds or protein concentrates. Such concentrates can contain, in addition to the active substances, also additives, vitamins, antibiotics, chemotherapeutics, bacteriostatics, fungistatics, coccidiostatics, hormone preparations, substances having anabolic activity or other substances which promote growth, influence the meat quality of fat stock animals or are useful in another way for the organism.

For peroral administration dosage units such as drages (sugar coated tablets), tablets, preferably contain 500 mg. of an active substance according to the invention, that is -80% of a compound of formula I. They are produced by combining the active substance with, e.g. solid pulverulent carriers such as lactose, saccharose, sorbitol, mannitol; starches such as potato starch, maize starch or amylopectin, also laminaria powder or citrus pulp powder; cellulose derivatives or gelatine, optionally with the addition of lubricants such as magnesium or calcium stearate or polyethylene glycols to form tablets or drage cores. The latter are coated, e.g. with concentrated sugar solutions which can also contain, e.g., gum arabic, talcum and/or titanium dioxide, or with a lacquer dissolved in easily volatile organic solvents or mixtures of solvents. Dyestuffs can be added to these coatings, e.g. to distinguish between varying dosages of active substance.

The following prescriptions further illustrate the production of tablets and drages:

(a) 1000 g. of 2-(4'-isothiocyanophenyl)-benzimidazole hydrochloride are mixed with 550 g. of lactose and 292 g. of potato starch, the mixture is moistened with an aqueous solution of 8.0 g. of gelatine and granulated through a sieve. After drying, 60.0 g. of potato starch, 60.0 g. of talcum, 10.0 g. of magnesium stearate and 20.0 g. of colloidal silicon dioxide are mixed in and the DETERMINATION OF THE ANTHELMINTIC AC- TION ON HENS INFESTED WITH ASCARIDIA GALLI One to three day old chickens are infested with eggs of Ascariaia galli (rnaw worms). Groups of 5 hens were used for each test. Four to five weeks after infestation, the active substances were administered to the hens in one dose on three consecutive days. Hens infested but not treated served as controls.

EVALUATION The number of Ascaridia galIi excreted by each group of tested hens within 5 days after the first administration of the active substance was determined daily and the number of worms found in the intestine after killing on the 5th day was also added. In addition the number of hens free from worms was determined.

No. ot'Ascaridia gulli from 5 hens Excreted during test.

Daily In per- Infestation dose, Absocent of Found of the test Ing /kg. lute total on disanimals on General Active substance weight No. No. section dissection condition a. 2- (4-isothiocyanostyryl)-benzimidazo1e hydrochloride hydrate 500 106 97 3 00012 Good. b. 2-(4-isothiocyanostyryl)-5-chlorobenzimidazole hydrochloride hydra 500 47 98 1 0-0-0-0-1 D0. 0. 2-pheuyl-5-isothiocyano-benzimidazole hydrochloride 500 42 98 1 0-0-0-0-1 Do d 2'(4-isothiocyanostyryl) -benzoxazole 500 34 100 0 0 Do. 0 2-(4-isothiocyanostyryl)-5-methoxybenzimidazole h rochlo 500 90 98 2 0-0-002 Do. f 2-(4-isothiocyanophenyl)-benzi1nidazo1e hydrochloride 500 49 100 0 0 Do. g 2-(3-isothiocyanostyryl)-5-chlorobenzimidazole hydrochloride 500 143 100 0 Do. h 2'(4-isothiocyanophenyl)-5-chlorobenzimid azole hydrochloride. 500 97 99 1 0-0-001 Do. i 1-methyl-2- (3-isothiocyanostyryl)-b enzimidazole- 500 98 1 0-0-0-0-1 Do. j 2-(3-isothiocyanophenyD-benzimidazole 500 98 97 3 008-00 Do. k 2- (4-is0thi0cyanophenyl)-benzimidazole 3 0 0 Do. 1.-.. 2-[2-(4"-isothiocyenophenyl)-ethyl-benzoxazole 500 166 99 1 01-000 Do. 111... 2-(2-(4"-isothiocyanophenyl)-ethyl -5-chloro-benzimidazo1e hydrochloride- 500 200 98.5 3 2-1-0-0-0 D0. 11 2-(2,4J-dichlorostyryl)-5-is0thiocyano-benzimidazole hydrochlonde 500 133 99 1 0-0-0-1-0 Do.

0 S-methylallyloxy-isothiocyanobenzene (known from German Patent No.

750 171 100 0 0 4/5 exitus. p 2-phenylbenzimidazole (known from U.S. Patent No. 3,080,282) 1, 000 69 36 7-5273227 Good. q 2-(4-thiazolyl)-benzimidazole (known from U.S. Patent No. 3,017,415) 500 131 100 0 0 Do.

mixture 1S pressed into 10,000 tablets each welghing 200 TESTS ON MICE INFESTED WITH HYMENOLEPIS mg. and containing 100 mg. of active substance. If de- NANA sired, the tablets can be grooved for better adaptation of the dosage.

(b) A granulate is produced from 1000 g. of 2-(4'-isothiocyanophenyl)-5-chloro-benzimidazole hydrochloride, 379 g. of lactose and the aqueous solution of 6.0 g. of gelatine, After drying, the granulate is mixed with 10.0 g. of colloidal silicon dioxide, 40.0 g. of talcum, 60.0 g. of potato starch and 5.0 g. of magnesium stearate and the mixture is pressed into 10,000 drage cores. These are then coated with a concentrate syrup made from 533.5 g. of crystallised saccharose, 20.0 g. of shellac, 75.0 g. of gum arabic, 250 g. of talcum, 20 g. of colloidal silicon Hymenolepis mma Daily Time Infestation Infestation dose, adminof the 5 test of control nag/kg istered animals on animals on Active substance weight in days dissection dissection a 2-(4-isothiocyanostyryl)-5-chlorobenzimidazole hydrochloride hydrate 500 3 0 8-4-8-2-7 b 2-phenyl-5-isothiocyanobenzimidazole hydrochloride 600 3 0 445-7-1-2 c- 2-(4'-isothiocyanostyryD-benzoxazole 600 3 0 6-8-17-19-5-16 d 1-(4-to]yl)-2-(3"-isothiocyanostyryl)-5-isothioyano azo 750 3 0 7-11-14-10-2 e. 2-(3,4-dichlorostyryl)-5-isothiocyanobenzimidazole hydrochloride 750 3 0 7-14-14-84 L 1-methy1-2-(3-isothiocyanostyryD-benzirnidazole 650 3 0 1154-7-6 g 2-(3-isothiocyanostyryl)-5-methoxyb enzimidazole-hydrochloride 650 3 0 11547-6 h 2-(3-isothiocyanostyryl)-5,6-dimcthylbenzimidazole hydrochloride. 600 3 0 2-11-6-4-13 i-.. 2-(4-isothiocyanophenyl)-5-chlorobenzirnidazole 500 3 0 94-3-5-4 j- 2-phenyl-5-isothiocyano-benzimidazole 500 3 0 4-6-11-9-7 k. 2-(3-isothiocyanophenyl)-benzin1idazole 500 3 0 5-6-10-9-8 1... 2-(4-isothiocyanophenyl)-benzoxazo1e 750 3 0 m 2-[2-(4-isothiocyanophenyl)-ethy11-5-ch1orobenzimidnzole hydrochloride 500 3 0 826-9-4 n 3-butoxy-isothiocyano-benzene (known from German Patent N0. 852.087) 760 1 T T 1' T t o. 2-phenylbenzimidazole (known from U.S. Patent No. 3,0 0,282) 1,000 4 2-34-4-3 1-2-2-17-5 p 2-(4-thiazo1yl)-benzimidazolc (known from U.S. Patent No. 3,017,415) 1, 000 4 8-3-8-22-19 8 30-8-24-22 1 5/5 exitus.

7 8 TESTS ON RATS INFESTED WITH FASCIOLA Example 1 HEPA TICA (a) 20.9 Parts of 2-(4'-aminophenyl)-benzimidazole Wh te. lzboratory rats age infested wlti h l i'l f fiuhes are added in portions to a well stirred emulsion of 15.4 if 312 1; g qgg au lf's is (122 13312223 b fl parts of thiophosgene in 120 parts by volume of ice water. y 1 y y On completion of the addition, the mixture is stirred for 8 droppings made at 3 different times.

For each test, two infested rats were forcibly fed with hours at room .temperature' The prclpitate 1S f 'w well washed with water, after drying in vacuo it iS disthe active substance in the form of a sus ension once p persed with acetone and again filtered. 2-(4'-isothiocyanodaily on three consecutive days. Analysis of droppings was made once in the third week and once in the fifth phenyl)-benz1m1dazole hydrochloride hydrate are obweek after administration of the active substance to detertamed 251-2530- mine the content of liver flukes. At the end of the fifth Parts of the above hydrochloride are Well t iweek after the beginning of the test, the test animals were thrilled with 250 Parts y Volume of 2N Sodium Carbonate killed and the presence of liver flukes was determined. solution and filtered off. The filter residue is washed well,

Faacioltz hepatz'ca Control of excretion for eggs 3 times Dally Number of dose, Before After liver flukes mg. /kg. rnedicar medicaafter A ti substance weight tion tion dissection a 2-(3',4-dichlorostyryl)-5-isothiocyanobenzimidazole hydrochloride 100 P iti Negative 0 b 2-(4-isothiocyanostyryl)-5-chl0robenzimidazolc hydrochloride hydrate 200 do do 0 c 2-(4-isothiocyanostyryl)-benzimidazole hydrochloride 0 d 2-(4-isothioeyanophenyl)-5-chlorobenzimidazole hydrochloride"... 0 e 2-(3-isothiocyanostyryl)-5-methoxy-benzimidazole hydrochloride... 0 f.-. 2-(3'-isothiocyanostyryl)-5,6-dimethy1-benzimidazole hydrochloride 0 g. 2-(3-isothiocyanophenyl)-benzlmidaole. 0 h 2-(4'-isothiocyanophenyl)-benzimidazole... 0 2-[2-(4"-isothiocyanophenyl)-ethyl -5- hlorobenzimldazole hydrochloride... 0 2-[2-(4-isothioeyanophenyl)-ethyl -5-methoxybenzimidazole hydrochloride o k 2-pheny1benzimidazole (known from U.S. Patent No. 8,080,282) 200 positivm" 1 2-(4-thiaz0lyl)-benzimidazole (known from U.S. Patent No. 3 017,415) 200 d "do m a-methylallyloxy-isothioeyanobenzene (known from German 1 atent No. 852,087) 100 Negative" (1) l 0-0 2/4 exitus. TESTS ON MICE INFEST-ED WITH SCHISTOSOMA first with water and then with acetone. The free base is MANSONI obtained. M.P. 242-245. Groups of 5 mice each, which had been infested with Example 2 cercariae of Schistosoma mansoni for a period of days 42 Parts of 2 (334' dich1orostyry1 s aminobenzimid were forcibly fed Wlth h actlve Substance 111 the r azole are dissolved in 100 parts by volume of dioxane and Of a suspehslon da11y 0n five P- ten consecutlve the solution is added dropwise to an emulsion of 18.3 parts y After each Perlod 0f 11, f days FP- 40 of thiophosgene in 200 parts by volume of ice water while counting from the first day admlmstrahon of active stirring well. After stirring for 12 hours at room tempera- Suhstancer a g hlf of test ammals was kllled and the ture, the precipitate which has separated out is filtered off number of remaining male and female adultand washed, first with water and then with acetone. After Schistosomae in the liver and in the peritoneum was deterd i in vacuo, 2- 3',4' i hl -5 i mined. Difference as made between hvmg and dcad benzimidazole hydrochloride decomposes at 280-305 parasites. Equally sized groups of mice infested simulbli i at over 240) taneously but not treated served as controls.

The agents were tolerated by the mice without any Example 3 symptoms, 33.6 'Parts of 2-(4'-aminophenyl)-benzoxazol are added Schistosama 'mimsoni Infestation of the 5 test animals on dissection atedDaily d'llllnme 050 in a n- 6th da 11th (1 g g istered y ay 21st day 31st day Active substance weight In y 0" 9 d 9 d 9 d 9 Liver 8 8 5 {Perit0neum. o 2-(4-is0thi0 yanopheny1)-benz1m1dazo1e'hydroehlonde 120 10 {Liver T14 112 0 0 Peritoneum. 0 0 0 0 0 2-(4'-isothioeyanophenyl)-5chlorobenzimidazole-hydrochloiide 240 10 {im k T i T 3 (3 1 3 i Liver ..I 27 14 Controls. {Peritoneum 3 4 i3 i h? N orn.-i'=Dead trematodes.

It follows from the preceding test tables that the known in portions to a well stirred emulsion of 20 parts of thiocompounds used for comparison are either too toxic in phosgene in 200 parts by volume of ice water. On comtherapeutically active o and, n smaller doses, pletion of the addition, the mixture is stirred for 8 hours effefitive 1' y lhsllfhclehlly effechver that y at room temperature; then the precipitate is filtered off y effective against one kind of helmrnths, e against well washed with water, and dried. After recrystallization nematodes l Worms) not agamst cestodes and from acetone, 2-(4'-isothiocyanophenyl)-benzoxazole is trematodes or viceversa. obtained M The isothiocyano-benzazoles according to the invenp tion, however, possess an excellent polyvalent activity against all of the different classes of helrninths tested.

The following examples serve to illustrate the produc- 'lsothlocyanostyryl) 15 Obtained y tion Processes according to the invention where not the same procedure as described in Example 3 from 20.5 otherwise stated, parts" mean parts by weight. The tem- P of y y Parts of peratures are given in degrees Centigrade. thiophosgene in parts by volume of ice water. After Example 4 9 recrystallisation from ether/petroleum ether, it melts at 79-80.

Example 15.1 Parts of 2-(4'-aminophenyl)-benzoxazole and 11.4 parts of N,N-diethylthiocarbamoyl chloride are refluxed in 200 parts by volume of dry toluene for 4 hours. The hot solution is filtered, the filtrate evaporated, the crystalline residue recrystallized from acetone, and thus 2-(4'-isothio cyanophenyl)-benzazole obtained. M.P. 157158.

Example 6 Hydrogen chloride is introduced under cooling for a period of 90 minutes into a suspension of 10.5 parts of 2-(4-aminophenyl)-benzoxazole and 15.4 parts of bis-diethyl-thiocarbamoyl disulfide in 250 parts by volume of dry chlorobenzene. The reaction mixture is then refluxed for 4.5 hours, and subsequently heated with active char coal and filtered While hot. The filtrate is evaporated and the residue recrystallised from acetone/toluene to yield 2-(4-isothiocyanopheny l)-benzoxazole which melts at 157-159.

Example 7 10.5 Parts of 2-(4'-aminophenyl)-benzoxazole, 7.4 parts of bis-trichloromethanesulfenyl trithiocarbonate (bis-trichloromethyl pentathio-dipercarbonate) and 50 parts by volume of water are stirred together at room temperature for 14 hours. The resulting viscous precipitate is separated, washed with water, and, after drying in vacuo at 60", it is treated with hot acetone. The resulting solution is filtered, toluene is added, and the solution is then concentrated until a crystalline precipitate is formed. The thus obtained 2 (4 isothiocyanophenyl) benzoxazole melts at 157159.

Example 8 Parts of phosgene are introduced at 0' into 100 parts by volume of chlorobenzene and then 10.5 parts of 2-(4- aminophenyl)-benzoxazole added. The resulting suspension is stirred over night at room temperature. A slight stream of phosgene is then introduced while the suspension is heated up to 90 over a period of 45 minutes. The addition of phosgene is then stopped and the temperature raised to l-130. At this temperature the mixture is stirred for about 2 hours until the evolution of gas has stopped completely. After slowly cooling to room tem-,

perature 3.75 parts of phosphorus pentasulfide are added, and the resulting mixture heated to reflux temperature under stirring for 14 hours. After filtration while still hot, the filtrate is evaporated and the residue recrystallised from acetone/toluene to yield 2-(4-isothiocyanophenyl)- benzoxazole. M.P'. 157-159".

Example 10 A solution of 15.1 parts of 2- (4-aminopheny-l)-benzoxazole in 360 parts by volume of dry ether is cooled to -10 to --5 and first 31 parts by volume of triethylamine and then 4.3 parts by volume of carbon disulfide are added dropwise. The resulting brown suspension is stirred at room temperature for about 12 hours, cooled to 0, and 6.7 parts by volume of phosphorus oxychloride in 80 parts by volume of dry ether are added dropwise over a period of minutes, keeping the temperature at Example 11 To a solution of 17 parts of ammonium rhodanide in 200 parts by volume of dry acetone are added 31 parts of benzoyl chloride under stirring. The suspension is heated to reflux temperature and, after 5 minutes, the hot solution of 46 parts of 2-(4'-aminophenyl)-benzoxazole in 400 parts by volume of acetone is added. After stirring for another 2 minutes at reflux temperature the mixture is poured into 5000 parts of ice water. The precipitate is filtered off, Washed with water and suspended in 350 parts by volume of 10% sodium hydroxide. The suspension is quickly heated to boiling temperature and kept boiling for about 2 minutes. The resulting solution is cooled in an ice bath, neutralized with 2N hydrochloric acid, and brought to pH 8 with 2N ammonia. The precipitate is filtered off, Washed with water until neutral, and dried at in vacuo. The finely powdered material is suspended in 500 parts by volume of dry chlorobenzene and refluxed for 14 hours. The clear solution is then evaporated, the residue recrystallised from acetone, and 2-(4-isothiocyanophenyl)-benzoxazole is obtained. M.P. 157458.

Example 12 (a) 12.4 Parts of N-(Z-hydroxyphenyl)-(4-amino)- benzaldimine hydrochloride are dissolved in 150 parts of ice water. After the addition of parts by volume of chloroform and 34 parts of sodium bicarbonate, 4.4 parts by volume of thiophosgene in 20 parts by volume of chloroform are added dropwise. The resulting emulsion is stirred for 6 hours at room temperature. The chloroform phase is separated, dried with potassium carbonate, treated with active charcoal, filtered, and the filtrate evaporated. The oily residue is dissolved in 100 parts by volume of acetone, and the N-(2-hydroxyphenyl)-(4'-isothiocyano) benzaldimine is precipitated by the addition of ether. Decomposition P. 210.

(b) 5.3 Parts of the benzaldimine obtained under (a) and 5.3 parts of chloranil in parts by volume of xylene are refluxed for 4 hours. The reaction mixture is filtered while hot, the filtrate evaporated, and the oily residue recrystallised from acetone/toluene. The thus obtained 2- (4-isothiocyanophenyl)-benzoxazole melts at 156-158.

Example 13 14.4 Parts of 2-(3-isothiocyanophenyl)-benzimidazole hydrochloride and 17 parts of potassium carbonate are stirred in 500 parts by volume of dry acetone for 60 minutes at reflux temperature. 6.3 Parts by volume of benzoyl chloride in 50 parts by volume of dry acetone are then added dropWise. After stirring for 6 hours at reflux temperature the reaction mixture is filtered While hot, the filtrate evaporated, the oily residue taken up in toluene and treated with active char coal and the purified product eventually recrystallised from ether. 1-Benzoyl-2-(3'-isothiocyanophenyl)-benzimidazole is thus obtained. M.P. 124-125 Example 14 A solution of 25 parts of 2-(4-isothiocyanophenyl)- benzimidazole and 200 parts by volume of acetone is kept at 20 while a slow stream of hydrogen bromide is introduced until no further precipitate is formed. The precipitate is filtered off washed with acetone and dried. The 2- (4'-isothiocyanophenyl)-benzimidazole hydrobromide is thus obtained, M.P. 260-280 (D.).

In an analogous manner there are obtained the compounds falling under Formulas Ia through Ii, below, in which R through R, and R represent the substituents given in the respective columns of the following Table I TABLE V 2-styry1benz1midaz01es oi the formula:

Salt

Number HmHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHm mm HHHHHHCCHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH tn H N S 8-0888 SOSSSSSSSSSCS SS C 0%, 000 CNOOCOCCCCOOC CC NONH NNN NHNNNNNNNNNON NN N H H 1 Decomposes.

TABLE VI 2-styrylbenzimldazo1es (l-substituted) of the fol 'xmulaz R CCH=CH- N l R Number HHHHHHHHHHHHHHHHHHHHHHHHHEHH HHHHHHHHHHHHHHHHHHHHHHHHHHHH SSSS COCO HHHHmHHHwHHHHHHHHHHHH 1 Decomposes.

wherein one or two of R R R R and R is isothiocyano, with no more than one isothiocyanogroup on each ring;

one of R and R, (if not isothiocyano) is hydrogen, chlorine, bromine, nitro, tritiuoromethyl, carboxyl, lower alkyl, lower alkoxy, lower alkylthio or lower alkanoylamino; and the other of R and R, (if not isothiocyano) is hydrogen or lower alkyl;

each of R and R; (if not isothiocyano) is hydrogen, =hydroxyl, chlorine, lower 'alkyl or lower alkoxy;

R (if not isothiocyano) is hydrogen, chlorine,

bromine, hydroxyl, nitro, trifluoromethyl, carboxyl, carbamoyl, lower alkyl, lower alkoxy, lower alkylthio, lower alkylamino, lower alkoxycarbonyl, di-(lower alkyl) carbamoyl, di-(lower alkyl)-amino, lower alkanoyl-amino, lower alkenyloxy, lower alkenylthio, lower alkanoyloxy or lower alkanoyl;

each of R and R is hydrogen or R and R, together with the carbon atoms of ring A to which they are linked represents a benzene ring fused to ring X is oxygen or the grouping NR in which R represents hydrogen, lower alkyl, di-(lower alkyl)- amino lower alkyl, benzoyl-lower alkyl, halogenobenzoyl-lower alkyl, benzyl, phenyl, lower alkylphenyl, lower alkanoyl, benzoyl or halogenobenzoyl;

Z represents -CH CH or -CH=CH;

n is or 1; and

wherein no isothiocyano group occupies a position other than ortho to any hydroxyl or alkylamino group on the same ring, and wherein R may not be isothiocyano when X represents NH and n is 0; and

(b) when X in said compound represents NR, an

addition salt of said compound with an acid of sufficient strength to form such salt with said NR group;

and a compatible carrier.

2. A method for controlling helminths, comprising applying, by means of oral administration or stomach tube, to a warm-blooded animal infested therewith an anthelmintically effective amount of a compound as defined in Claim 1.

3. The method as defined in Claim 2, wherein said compound is 2-(4-isothiocyanophenyl)-benzimidazole or an addition salt thereof with an acid.

4. The method as defined in Claim 2, wherein said compound is 2 (4'-isothiocyanophenyl)-5-chloro-benzimidazole or an addition salt thereof with an acid.

5. The method as defined in Claim 2, wherein said compound is 2 [2'-(4"-isothiocyanophenyl)-ethyl]-5- methoxy-benzimidazole or an addition salt thereof with an acid.

6. The method as defined in Claim 2, wherein said compound is 2-(3'-isothiocyanostyryl)-5-chloro-benzimidazole or an addition salt thereof with an acid.

7. The method as defined in Claim 2, wherein said compound is 2-(3'-isothiocyanostyryl)-5,6-dimethyl-benz imidazole or an addition salt thereof with an acid.

8. The method as defined in Claim 2, wherein compound is 2-(4'-isothiocyanophenyl)-benzoxazole.

9. The method as defined in Claim 2, wherein compound is 2-(4-isothiocyanostyryl)-benzoxazole.

said

said

References Cited UNITED STATES PATENTS 3,080,282 3/1963 Shunk 260-309.2 3,262,929 7/ 1966 Okubo et al 260-240D 3,586,670 6/1971 Brenneisen 424273 VINCENT D. TURNER, Primary Examiner US. Cl. X.R. 424-273 Patent No. 3,822,356 Dated July 2, 1974 Inventor) y Paul 'Brenneisen and Alfred Margot It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The following "statement should appear in the heading:

Claims priority S it l d July 26, 1967, No. 10628/67.

Signed and sealed this 29th day of October 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents FORM po'wso (10459) uscoMM-Dc 60376-P69 ",5. GOVERNMENT PRINTING OFFICE 1N9 0-3'6-334, 

